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- Written by: Lake County News reports
An outbound comet that provided a nice show for skywatchers late last year is the target of an ongoing investigation by NASA's Swift satellite.
Formally designated C/2009 P1 (Garradd), the unusually dust-rich comet provides a novel opportunity to characterize how cometary activity changes at ever greater distance from the sun.
A comet is a clump of frozen gases mixed with dust. These "dirty snowballs" cast off gas and dust whenever they venture near the sun. What powers this activity is frozen water transforming from solid ice to gas, a process called sublimation. Jets powered by ice sublimation release dust, which reflects sunlight and brightens the comet.
Typically, a comet's water content remains frozen until it comes within about three times Earth's distance to the sun, or 3 astronomical units (AU), so astronomers regard this as the solar system's "snow line."
"Comet Garradd was producing lots of dust and gas well before it reached the snow line, which tells us that the activity was powered by something other than water ice," said Dennis Bodewits, an assistant research scientist at the University of Maryland, College Park, and the study's lead investigator. "We plan to use Swift's unique capabilities to monitor Garradd as it moves beyond the snow line, where few comets are studied."
Comets are known to contain other frozen gases, such as carbon monoxide and dioxide (CO and CO2), which sublimate at colder temperatures and much farther from the sun.
These are two of the leading candidates for driving cometary activity beyond the snow line, but phase transitions between different forms of water ice also may come into play.
C/2009 P1 was discovered by Gordon J. Garradd at Siding Spring Observatory, Australia, in August 2009. Astronomers say that the comet is "dynamically new," meaning that this is likely its first trip through the inner solar system since it arrived in the Oort cloud, the cometary cold-storage zone located thousands of AU beyond the sun.
Comet Garradd was closest to the sun on Dec. 23, 2011, and passed within 118 million miles (1.27 AU) of Earth on March 5, 2012. The comet remains observable in small telescopes this month as it moves south though the constellations Ursa Major and Lynx.
Although Swift's prime task is to detect and rapidly locate gamma-ray bursts in the distant universe, novel targets of opportunity allow the mission to show off its versatility. One of Swift's instruments, the Ultraviolet/Optical Telescope (UVOT) is ideally suited for studying comets.
The instrument includes a prism-like device called a grism, which separates incoming light by its wavelength.
While Swift's UVOT cannot detect water directly, the molecule quickly breaks up into hydrogen atoms and hydroxyl (OH) molecules when exposed to ultraviolet sunlight.
The UVOT detects light emitted by hydroxyl and other important molecular fragments – such as cyanide (CN), carbon monosulfide (CS) and diatomic and triatomic carbon (C2 and C3, respectively) – as well as the sunlight reflected off of cometary dust.
"Tracking the comet's water and dust production and watching its chemistry change as it moves deeper into the solar system will help us better understand how comets work and where they formed," said Stefan Immler, a researcher and Swift team member at NASA's Goddard Space Flight Center in Greenbelt, Md.
Swift last observed the comet on April 1, when it was 1.53 AU away and just past the orbit of Mars. Although detailed results are not yet available, Bodewits estimates that Comet Garradd was shedding about 400 gallons of water each second -- enough to fill an Olympic-size swimming pool in under 30 minutes.
But the water given off by the comet was only about half of the dust mass it produced. Bodewits estimates that each second, Garradd was losing about 7,500 pounds (3.5 metric tons, or about twice the typical mass of a small car) in the form of dust and icy grains.
Thanks to Garradd's brightness and the UVOT's sensitivity and resolution, researchers can monitor the comet when it is beyond the grasp of most ground-based observatories. Plans call for observations at eight different distances from the sun out to about 5.5 AU, which the comet will reach in April 2013.
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- Written by: Lake County News reports
LAKEPORT, Calif. – Kitten season is arriving early in Lake County this year, and these three little kittens are among the first of the season to be put up for adoption at Lake County Animal Care and Control.
They're about 6 weeks old and come in a variety of colors – calico, orange tabby and black.
Lake County Animal Care and Control is located at 4949 Helbush in Lakeport, next to the Hill Road Correctional Facility.
Office hours are Monday through Friday, 8 a.m. to 5 p.m., and 1 p.m. to 3 p.m., Saturday. The shelter is open from 10:30 a.m. to 4:30 p.m. Monday through Friday and on Saturday from 1 p.m. to 3 p.m.
Visit the shelter online at http://www.co.lake.ca.us/Government/Directory/Animal_Care_And_Control.htm .
To fill out an adoption application online visit http://www.co.lake.ca.us/Government/Directory/Animal_Care_And_Control/Adopt/Dog___Cat_Adoption_Application.htm .
For more information call Lake County Animal Care and Control at 707-263-0278.
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- Written by: Lake County News reports
In the midst of an emergency, a member of the public may have to call 911.
It is the calm voice and gentle demeanor at the other end of the phone that can help soothe rattled nerves and calm a stressful situation.
The U.S. Congress has designated the second full week of April of each year as National Public Safety Telecommunicators Week.
The California Highway Patrol (CHP) this week is taking the opportunity to thank communication workers who are on the front line of emergency response.
“The dedicated public safety dispatchers you speak with at our communications centers throughout the state are highly trained professionals. In an emergency, they may be the first person within our agency that you may come in contact with,” said CHP Commissioner Joe Farrow. “We are proud of the vital and often life-saving services they provide on a daily basis.”
CHP dispatchers often have challenging and stressful jobs since they take the majority of California’s wireless 911 emergency and non-emergency calls.
Dispatchers ensure the appropriate assistance is provided, whether it is sending an officer to respond to a call, or contacting fire, ambulance, or other emergency services.
In addition, they are in constant radio communication with the patrol officers, often assisting them by looking up vehicle identification, license plate and driver license numbers, or by running checks for wanted subjects.
The CHP has 25 communications/dispatch centers statewide that employ nearly 900 public safety dispatchers.
Last year, these individuals were responsible for handling approximately 9.3 million calls for service (911 and other calls).
Calling 911 during a stressful incident can be intimidating.
The following tips are designed to help callers through an emergency:
- No matter what happens – stay calm.
- Be prepared to provide your name, phone number, address or location, and a detailed description of the incident being reported.
- Let the dispatcher guide the conversation.
- Wait for the dispatcher to ask questions, then answer clearly and calmly.
- Listen carefully and follow all directions provided by the dispatcher.
- Be prepared to provide a physical description if an emergency involves a criminal suspect.
- Cellular telephones may not tell the call-taker where you are. Use a landline to report an emergency whenever possible.
- Remember, 911 is for life-threatening emergencies. Misuse of the emergency 911 system will result in a delay for callers with real emergencies and is punishable by a fine of not more than $1,000.
“We commend the employees who provide radio, telephone, and computer services to the public and CHP officers in the field, and we appreciate their continued dedication and professionalism,” Farrow added.
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- Written by: Dauna Coulter
In the opening lines to The Waste Land, T.S. Eliot wrote, “April is the Cruelest Month.”
You might agree if you live in the southeastern United States. Last April, a historic outburst of 202 tornadoes turned broad swaths of that part of the country into a disaster zone.
“The event of April 27 and 28, 2011, was the costliest convective storm in U.S. History,” said Kevin Knupp, professor of atmospheric sciences at the University of Alabama-Huntsville.
And he doesn't just mean costly in terms of property damage – 316 people lost their lives.
Of the 202 twisters that day, 62 tore through Alabama, where Knupp works. Ten of them were ranked EF 4 and 5 on the Enhanced Fujita Scale.
Three tornadoes churned paths more than 120 miles long, and a large number of the twisters cut swaths more than a half mile wide.
Knupp saw the results firsthand, and he’s been studying them ever since.
Aided by a team of graduate students and colleagues, he’s sifted through gigabytes of data1 collected by NASA and NOAA satellites and local ground sensors.
A year later, they have drawn some interesting conclusions.
One discovery was how rapidly an EF-5 spun up near the small town of Hackleburg, Alabama.
“The Hackleburg storm got its act together really quickly,” said Knupp.
This particular twister formed only 50 minutes after the underlying thunderstorm appeared. For comparison, the average time for tornado formation is 2 hours.
The twister blasted through north Alabama with winds over 200 miles per hour, killing 72 people.
Knupp’s team believes that something called a “thermal boundary” set the stage for the birth of the killer. Cool, moist air on one side of the boundary formed a low cloud base – “kind of like a wall,” he explained.
Warm air from the storm ran into the wall and swept upward. Updrafts are a key ingredient of tornadoes. In this case, updrafts as swift as 75 feet per second were recorded.
They also noticed that many of the tornadoes seemed to cluster in space and time. Knupp offers the example of Arab and Guntersville, neighboring communities not far from NASA’s Marshall Space Flight Center: “Sixteen tornadoes touched down in the area – 13 of them in a half hour period.”
Could local topography have attracted the twisters?
There does appear to be a link between the shape of the landscape and the path of these tornadoes.
“Arab-Guntersville is in a valley between two mountain ridges, and valleys can channel the flow of air, like in a breezeway,” noted UA-Huntsville atmospheric scientist Tim Coleman, a member of the research team.
Coleman also noticed a correlation between the slope of the terrain and the onset of damage tracks. “Winds intensified on the downward slopes of mountains in the area—and that is sometimes where the damage path starts,” he said.
He has observed this phenomenon in past tornadoes in east Tennessee and southern Virginia.
This tornado-topography hypothesis might seem obvious, but researchers have not always had enough data to test it – that is, not until April 2011.
Prompted in part by the outbreak, Coleman has studied tornado paths all over the southeast and found some interesting repeats.
For example, just north of Birmingham, several violent tornadoes have tracked within a 10-mile wide band since 1977. A similar track appears to the north and west of Huntsville.
“More research is needed to see if topography really plays a role,” cautioned Coleman. “The more we can learn, the more accurate we can make tornado warnings.”
They’re likely to get more data in the near future. It is April, after all.
Dauna Coulter works for the National Aeronautics and Space Administration.